"When asked what has changed in 2012, he didn't really provide an answer," Primack writes. "Just seems like the right opportunity hasn't presented itself (although he apparently is working on a new deal that may or may not close before January)."

Wilson isn't the only investor who's been gun-shy this year. Benchmark's Matt Cohler has yet to lead a deal in 2012, Primack points out. The same goes for Sequoia Capital's Roelof Botha, who hasn't lead a Series A investment in the past twelve months.